// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) Fuzhou Rockchip Electronics Co.Ltd
 * Author:Mark Yao <mark.yao@rock-chips.com>
 */

#include <drm/drm.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_probe_helper.h>

#include "rockchip_drm_drv.h"
#include "rockchip_drm_gem.h"
#include "rockchip_drm_fb.h"
#include "rockchip_drm_fbdev.h"

#define PREFERRED_BPP 32

static int rockchip_fbdev_mmap(struct fb_info *info, struct vm_area_struct *vma)
{
    struct drm_fb_helper *helper = info->par;
    struct rockchip_drm_private *private = helper->dev->dev_private;

    return rockchip_gem_mmap_buf(private->fbdev_bo, vma);
}

static const struct fb_ops rockchip_drm_fbdev_ops = {
    .owner = THIS_MODULE,
    DRM_FB_HELPER_DEFAULT_OPS,
    .fb_mmap = rockchip_fbdev_mmap,
    .fb_fillrect = drm_fb_helper_cfb_fillrect,
    .fb_copyarea = drm_fb_helper_cfb_copyarea,
    .fb_imageblit = drm_fb_helper_cfb_imageblit,
};

static int rockchip_drm_fbdev_create(struct drm_fb_helper *helper, struct drm_fb_helper_surface_size *sizes)
{
    struct rockchip_drm_private *private = helper->dev->dev_private;
    struct drm_mode_fb_cmd2 mode_cmd = {0};
    struct drm_device *dev = helper->dev;
    struct rockchip_gem_object *rk_obj;
    struct drm_framebuffer *fb;
    unsigned int bytes_per_pixel;
    unsigned long offset;
    struct fb_info *fbi;
    size_t size;
    int ret;

    bytes_per_pixel = DIV_ROUND_UP(sizes->surface_bpp, 0x8);

    mode_cmd.width = sizes->surface_width;
    mode_cmd.height = sizes->surface_height;
    mode_cmd.pitches[0] = sizes->surface_width * bytes_per_pixel;
    mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp, sizes->surface_depth);

    size = mode_cmd.pitches[0] * mode_cmd.height;

    rk_obj = rockchip_gem_create_object(dev, size, true, 0);
    if (IS_ERR(rk_obj)) {
        return -ENOMEM;
    }

    private->fbdev_bo = &rk_obj->base;

    fbi = drm_fb_helper_alloc_fbi(helper);
    if (IS_ERR(fbi)) {
        DRM_DEV_ERROR(dev->dev, "Failed to create framebuffer info.\n");
        ret = PTR_ERR(fbi);
        goto out;
    }

    helper->fb = rockchip_drm_framebuffer_init(dev, &mode_cmd, private->fbdev_bo);
    if (IS_ERR(helper->fb)) {
        DRM_DEV_ERROR(dev->dev, "Failed to allocate DRM framebuffer.\n");
        ret = PTR_ERR(helper->fb);
        goto out;
    }

    fbi->fbops = &rockchip_drm_fbdev_ops;

    fb = helper->fb;
    drm_fb_helper_fill_info(fbi, helper, sizes);

    offset = fbi->var.xoffset * bytes_per_pixel;
    offset += fbi->var.yoffset * fb->pitches[0];

    dev->mode_config.fb_base = 0;
    fbi->screen_base = rk_obj->kvaddr + offset;
    fbi->screen_size = rk_obj->base.size;
    fbi->fix.smem_len = rk_obj->base.size;

    DRM_DEBUG_KMS("FB [%dx%d]-%d kvaddr=%p offset=%ld size=%zu\n", fb->width, fb->height, fb->format->depth,
                  rk_obj->kvaddr, offset, size);

    return 0;

out:
    rockchip_gem_free_object(&rk_obj->base);
    return ret;
}

static const struct drm_fb_helper_funcs rockchip_drm_fb_helper_funcs = {
    .fb_probe = rockchip_drm_fbdev_create,
};

int rockchip_drm_fbdev_init(struct drm_device *dev)
{
    struct rockchip_drm_private *private = dev->dev_private;
    struct drm_fb_helper *helper;
    int ret;

    if (!dev->mode_config.num_crtc || !dev->mode_config.num_connector) {
        return -EINVAL;
    }

    helper = devm_kzalloc(dev->dev, sizeof(*helper), GFP_KERNEL);
    if (!helper) {
        return -ENOMEM;
    }
    private->fbdev_helper = helper;

    drm_fb_helper_prepare(dev, helper, &rockchip_drm_fb_helper_funcs);

    ret = drm_fb_helper_init(dev, helper);
    if (ret < 0) {
        DRM_DEV_ERROR(dev->dev, "Failed to initialize drm fb helper - %d.\n", ret);
        return ret;
    }

    ret = drm_fb_helper_initial_config(helper, PREFERRED_BPP);
    if (ret < 0) {
        DRM_DEV_ERROR(dev->dev, "Failed to set initial hw config - %d.\n", ret);
        goto err_drm_fb_helper_fini;
    }

    return 0;

err_drm_fb_helper_fini:
    drm_fb_helper_fini(helper);
    return ret;
}

void rockchip_drm_fbdev_fini(struct drm_device *dev)
{
    struct rockchip_drm_private *private = dev->dev_private;
    struct drm_fb_helper *helper = private->fbdev_helper;

    if (!helper) {
        return;
    }

    drm_fb_helper_unregister_fbi(helper);

    if (helper->fb) {
        drm_framebuffer_put(helper->fb);
    }

    drm_fb_helper_fini(helper);
}
